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Electronic Control Module

The tractor engine equipped by Electronic Control Module (ECM) (1) with functions as a governor and a
computer for the fuel system. The ECM receives signals from the sensors in
order to control the timing and the engine speed. The electronic system
consists of the Electronic Control Module (ECM), the engine sensors and inputs
from the parent machine. The ECM is the computer. The personality module is the
software for the computer. The personality module contains the operating maps.
The operating maps define the following characteristics of the engine:

• Engine power

• Torque curves

• Engine speed (rpm)

• Engine Noise

• Smoke and Emissions

The factory passwords restrict changes to authorized personnel. Factory
passwords are required to clear any event code. The Electronic Control Module (ECM)
has an excellent record of reliability. Any problems in the system are most
likely to be the connectors and the wiring harness. The ECM should be the last
item in troubleshooting the engine. The personality module contains the software
with all the fuel setting information. The information determines the engine
performance. The personality module is installed behind the access panel on the
ECM. Flash programming is the method of programming or updating the personality
module.

Engine Speed Governor

The electronic controls determine the injection timing, the amount of
fuel that is delivered to the cylinders and the intake manifold pressure if an
electronically controlled wastegate is installed on the turbocharger. These
decisions are based on the actual conditions and the desired conditions at any
given time. The governor has software that compares the desired engine speed to
the actual engine speed. The actual engine speed is determined through the
primary speed/timing sensor and the secondary speed/timing sensor. If the desired
engine speed is greater than the actual engine speed, the governor injects more
fuel in order to increase engine speed.

Timing Considerations

Once the governor has determined the amount of fuel that is required, the
software must determine the timing of the fuel injection. Fuel injection timing
is determined by the ECM after considering input from the following components:

• Engine coolant temperature sensor

• The sensor for the intake manifold air temperature

• The sensor for the intake manifold pressure

At start-up, the ECM determines the top center position of the number 1
cylinder from the secondary speed/timing sensor in the fuel injection pump. The
Electronic Control Module (ECM) decides when fuel injection should occur relative
to the top center position. The ECM optimizes engine performance by control of
each of the electronic unit injectors so that the required amount of fuel is
injected at the precise point of the engine’s cycle. The electronic unit
injectors are supplied high pressure fuel from the fuel injection pump. The ECM
also provides the signal to the solenoid in the fuel injection pump. The
solenoid in the fuel injection pump controls a valve in the fuel injection
pump. This valve controls the pressure in the fuel injection pump. Fuel that is
not required for the engine is diverted away from the fuel injection pump back
to the fuel tank. The ECM adjusts injection timing and fuel pressure for the
best engine performance, the best fuel economy and the best control of exhaust
emissions. The actual timing can be viewed with an electronic service tool.
Also, the desired timing can be viewed with an electronic service tool.

Fuel Injection

The personality module inside the ECM sets certain limits on the amount
of fuel that can be injected. The FRC Limit is a limit that is based on intake manifold
air pressure and engine rpm. The FRC Limit is used to control the air/fuel
ratio in order to control the engine’s exhaust emissions. When the ECM senses a
higher intake manifold air pressure, the ECM increases the FRC Limit. A higher
intake manifold air pressure indicates that there is more air in the cylinder.
When the ECM increases the FRC Limit, the ECM allows more fuel into the
cylinder. The Rated Fuel Limit is a limit that is based on the power rating of
the engine and on the engine rpm.

The Rated Fuel Limit enables the engine power and torque outputs to conform
to the power and torque curves of a specific engine model. These limits are in
the personality module and these limits cannot be changed.

Speed/Timing Sensor

Timing wheel on the crankshaft

The primary engine position is a passive sensor. The timing wheel is
located on the crankshaft. The speed/timing sensor receives a signal from the
teeth on timing wheel. The extra space on the timing wheel gives one revolution per space. The space is oriented so that the space
is 40 degrees after top center.

Schematic for speed/timing sensor

When the engine is cranking, the ECM uses the signal from the speed/timing
sensor in the fuel injection pump. When the engine is running the ECM uses the
signal from the speed/timing sensor on the crankshaft. This speed/timing sensor
is the primary source of the engine position.

Pressure Sensors

Schematic for pressure sensors

The boost pressure sensor and the engine oil pressure sensor are active
sensors. The boost pressure sensor provides the ECM with a measurement of inlet
manifold pressure in order to control the air/fuel ratio. This will reduce the
engine smoke during transient conditions. The operating range of the boost
pressure sensors:

For standard power engines, the range is up to the following........ 339 kPa (49.169 psi).

For all high power engine, the range is up to the following............
440 kPa (63.818 psi).

The engine oil pressure sensor provides the ECM with a measurement of
engine oil pressure. The ECM can warn the operator of possible conditions that
can damage the engine. This includes the detection of an oil filter that is
blocked.

The air inlet temperature sensor and the coolant temperature sensor are
passive sensors. Each sensor provides a temperature input to the ECM. The ECM
controls following operations:

• Fuel delivery

• Injection timing

The operating range for the sensors..... 40 °C to 150 °C (40 °F to 302 °F)

The sensors are also used for engine monitoring.

Power Sources

Power Supplies

The 6 cylinder Tractor Engine supplies power to the ECM. The ECM powers
the following components:

• All sensors on the engine

• The solenoid for the fuel Injection Pump

• The solenoid for the Waste gate (optional)

• Diagnostic connector

• Electronic unit injectors

The glow plugs are powered directly from the battery

ECM Power Supply

Schematic for ECM

The power supply to the ECM and the system is drawn from the 24 volt or
the 12 volt battery. The power supply for the ECM has the following components:

• Battery

• disconnect switch

• Key start switch

• Fuses

• Ground bolt

• ECM connector

• Machine interface connector

The Schematic for the ECM shows the main components for a typical power
supply circuit. Battery voltage is normally connected to the ECM. The input from
the key start switch turns on the ECM. The wiring harness can be bypassed for troubleshooting
purposes. The display screen on the electronic service tool can be used in
order to check the voltage supply.

Power Supply for the Pressure Sensors

Schematic for pressure sensors

The ECM supplies 5.0 ± 0.2 DC volts through the ECM connector to each
sensor. The power supply is protected against short circuits. A short in a
sensor or a wiring harness will not cause damage to the ECM.